I checked a tiny bit of your post history - is this related to the health popup message that Scirra added? If so, there's really not much to say about it. Really thinking about it, I'd throw the suggestion "can this popup have a button to 'never remind me' so that I don't have to hunt in the settings for this?", or maybe mentioning that 2 hours should actually be 1 hour (many advise each other to take a 5 minute walk after sitting down for 1 hour), but beyond that, Scirra want this message in their product, it can be disabled, and... That's it. It may be true that this kind of message is not in other software (I've only seen it in MMO games), but it can be disabled with a couple of clicks. If it couldn't be disabled, then I'd bet many people would be louder about this on the forum. You made a new topic about this which was extremely sarcastic - sarcasm works as a joke a lot of the time and I love sarcasm, but it came off as abrasive when I read this, like when you mentioned "I wonder why no serious software does this.", which is a valid opinion to have, but just sounds like you think C3 is not serious software due to... a popup message. It comes off as exaggerated negativity. I appreciate a bit of spiciness on the forum, but I read your post thinking "...why not disable it?" .
For the record, I'm just a hardcore lurker on these forums, so I could be wrong about things, but I feel like I have a general idea of what to expect with locks and such.
I think the admins are generally fair with locking threads. As much as it sucks to have your topics locked, moderation is needed. Sometimes it will not work in our favour and it can be frustrating, but moderation is needed, otherwise this place could become a messy negative hell-hole of chaos, which would push current users away from the forum, and possibly confuse new users that visit.
The admins could make mistakes on what they lock, but that is like any website - anyone that tries to post on Reddit knows how often posts get locked for the most trivial things (I saw an interesting question on ELI5 the other day, clicked on it, and it was removed due to "use the search tool"... I wouldn't have even thought to search for the question that was posted!)
If a topic was locked unfairly, then I think other forum users might try and defend you if they saw this. But at the end of the day, it's Scirra's forum, they can suddenly decide to lock any post about "discussing competitor products" if they wanted to, but thankfully they have a nice philosophy of allowing a lot of discussion, even if you talk about a competitors product in a positive light (although if the topic was just insulting C3 whilst complimenting another game dev software, then that may get locked due to, well, nothing being gained from the conversation).
Some things have been discussed to death, such as "Can you make native export?", which is something many wish for, but it is not Scirra's goal with Construct. These topics may get locked quicker, but they usually post a link to some performance stats and such. But on the flip side, say someone found a tool to convert HTML5 into native somehow, then that would be an amazing thing to post and I'd hope someone shares this on the forum!
I wouldn't worry too much about topic getting locked. If there is a locked topic but you want to discuss a new point, then I'd suggest making new topic, mentioning that you saw a locked topic but had something to add. If that backfires, but you feel it is really important to ask, then you could always email their support.
If your OWN topic was closed, then I'd avoid making a new topic, as this could look like you're trying to circumvent the admin's decisions, which is against the rules. Email their support in this case.
I hope you enjoyed my wall of text.